Swine vesicular disease

Swine vesicular disease is a notifiable disease

Under Queensland legislation, if you suspect the presence of vesicular disease in pigs, you must report it to Biosecurity Queensland.

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Overview

Cause

Swine vesicular disease (SVD) is caused by a virus belonging to the family Picornaviridae.

Description

SVD is an acute, highly-contagious viral disease of pigs clinically indistinguishable from the other vesicular diseases of pigs, notably foot-and-mouth disease (FMD). Rapid identification of the virus is essential to rule out the presence of FMD.

Where the disease occurs

The disease was first recognised in Italy in 1966. In the early 1970s outbreaks occurred in Britain, Austria and Poland. Outbreaks occurred in Belgium, Italy and Spain in 1993 and again in Italy in 1998. It has also occurred in Japan, Taiwan and Hong Kong.

There have been no outbreaks in Australia.

The disease in animals

Clinical signs have only been observed in pigs and can be mild and easily missed. Early signs may be fever, loss of appetite, lethargy, unwillingness to stand and lameness. Pregnant sows may abort. Blisters appear around the top of the claws and between the main digits and burst about 36 hours later, leaving an ulcer. The usual clinical sign is 'thimbling' or separation of the horn or sole of the foot. Lesions may extend to lower limbs and occasionally abdomen, chest, teats and snout.

The incubation period is about seven days. Young pigs tend to show more severe clinical signs than adults.

Although up to 100% of animals may be clinically affected, deaths are rare.

Spread of the disease

Pigs become infected by direct contact with infected pigs or by eating infected pork products. Swill feeding has been responsible for most primary outbreaks and has contributed to the spread or recurrence of disease in many countries. Movement of infected pigs can also be a major factor in the spread of disease. There is no evidence for airborne spread.

It is a resistant virus only being destroyed by heating to 69°C, and resistant to inactivation by a wide number of disinfectants. It is very persistent in meat and meat products and can survive refrigeration and freezing for some time.

Control of the disease

The strategy in Australia is:

immediate stamping out to eliminate the source of virus by slaughter of affected animals

quarantine and movement controls to prevent spread

thorough decontamination

tracing and surveillance to determine the source and extent of disease

zoning to define infected and disease-free areas.

There is no useful role for vaccination in the control of swine vesicular disease.